Try multiple instances of the server

Tests/SessionTests.swift

@@ -7,20 +7,14 @@ private let defaultTimeout: TimeInterval = 10
 private let turboTimeout: TimeInterval = 30
 
 class SessionTests: XCTestCase {
-    private static let server = HttpServer()
+    private let server = HttpServer()
 
     private let sessionDelegate = TestSessionDelegate()
     private var session: Session!
 
-    override class func setUp() {
+    override func setUp() {
         startServer()
-    }
-
-    override class func tearDown() {
-        server.stop()
-    }
 
-    override func setUp() {
         let configuration = WKWebViewConfiguration()
         configuration.applicationNameForUserAgent = "Turbo iOS Test/1.0"
 
@@ -30,6 +24,8 @@ class SessionTests: XCTestCase {
 
     override func tearDown() {
         session.webView.configuration.userContentController.removeScriptMessageHandler(forName: "turbo")
+
+        server.stop()
     }
 
     func test_init_initializesWebViewWithConfiguration() {
@@ -141,7 +137,7 @@ class SessionTests: XCTestCase {
         return baseURL.appendingPathComponent(relativePath)
     }
 
-    private static func startServer() {
+    private func startServer() {
         server["/turbo-7.0.0-beta.1.js"] = { _ in
             let fileURL = Bundle.module.url(forResource: "turbo-7.0.0-beta.1", withExtension: "js", subdirectory: "Server")!
             let data = try! Data(contentsOf: fileURL)